Simplify EventMessageEncoder/Decoder serialization

We're no longer tied to the emsg spec, so we can skip unused fields
and assume ms for duration.

Also remove @Nullable annotation from EventMessageEncoder#encode, it
seems the current implementation never returns null

PiperOrigin-RevId: 262135009

library/core/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessageDecoder.java

@@ -15,22 +15,17 @@
  */
 package com.google.android.exoplayer2.metadata.emsg;
 
-import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.ParsableByteArray;
-import com.google.android.exoplayer2.util.Util;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 
 /** Decodes data encoded by {@link EventMessageEncoder}. */
 public final class EventMessageDecoder implements MetadataDecoder {
 
-  private static final String TAG = "EventMessageDecoder";
-
   @SuppressWarnings("ByteBufferBackingArray")
   @Override
   public Metadata decode(MetadataInputBuffer inputBuffer) {
@@ -43,15 +38,7 @@ public final class EventMessageDecoder implements MetadataDecoder {
   public EventMessage decode(ParsableByteArray emsgData) {
     String schemeIdUri = Assertions.checkNotNull(emsgData.readNullTerminatedString());
     String value = Assertions.checkNotNull(emsgData.readNullTerminatedString());
-    long timescale = emsgData.readUnsignedInt();
+    long durationMs = emsgData.readUnsignedInt();
-    long presentationTimeDelta = emsgData.readUnsignedInt();
-    if (presentationTimeDelta != 0) {
-      // We expect the source to have accounted for presentation_time_delta by adjusting the sample
-      // timestamp and zeroing the field in the sample data. Log a warning if the field is non-zero.
-      Log.w(TAG, "Ignoring non-zero presentation_time_delta: " + presentationTimeDelta);
-    }
-    long durationMs =
-        Util.scaleLargeTimestamp(emsgData.readUnsignedInt(), C.MILLIS_PER_SECOND, timescale);
     long id = emsgData.readUnsignedInt();
     byte[] messageData =
         Arrays.copyOfRange(emsgData.data, emsgData.getPosition(), emsgData.limit());

library/core/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessageEncoder.java

@@ -15,7 +15,6 @@
  */
 package com.google.android.exoplayer2.metadata.emsg;
 
-import androidx.annotation.Nullable;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
@@ -40,15 +39,12 @@ public final class EventMessageEncoder {
    * @param eventMessage The event message to be encoded.
    * @return The serialized byte array.
    */
-  @Nullable
   public byte[] encode(EventMessage eventMessage) {
     byteArrayOutputStream.reset();
     try {
       writeNullTerminatedString(dataOutputStream, eventMessage.schemeIdUri);
       String nonNullValue = eventMessage.value != null ? eventMessage.value : "";
       writeNullTerminatedString(dataOutputStream, nonNullValue);
-      writeUnsignedInt(dataOutputStream, 1000); // timescale
-      writeUnsignedInt(dataOutputStream, 0); // presentation_time_delta
       writeUnsignedInt(dataOutputStream, eventMessage.durationMs);
       writeUnsignedInt(dataOutputStream, eventMessage.id);
       dataOutputStream.write(eventMessage.messageData);

library/core/src/test/java/com/google/android/exoplayer2/metadata/emsg/EventMessageDecoderTest.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.emsg;
 
+import static com.google.android.exoplayer2.testutil.TestUtil.createByteArray;
+import static com.google.android.exoplayer2.testutil.TestUtil.joinByteArrays;
 import static com.google.common.truth.Truth.assertThat;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -30,18 +32,19 @@ public final class EventMessageDecoderTest {
 
   @Test
   public void testDecodeEventMessage() {
-    byte[] rawEmsgBody = new byte[] {
+    byte[] rawEmsgBody =
-        117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
+        joinByteArrays(
-        49, 50, 51, 0, // value = "123"
+            createByteArray(117, 114, 110, 58, 116, 101, 115, 116, 0), // scheme_id_uri = "urn:test"
-        0, 0, -69, -128, // timescale = 48000
+            createByteArray(49, 50, 51, 0), // value = "123"
-        0, 0, -69, -128, // presentation_time_delta = 48000
+            createByteArray(0, 0, 11, 184), // event_duration_ms = 3000
-        0, 2, 50, -128, // event_duration = 144000
+            createByteArray(0, 15, 67, 211), // id = 1000403
-        0, 15, 67, -45, // id = 1000403
+            createByteArray(0, 1, 2, 3, 4)); // message_data = {0, 1, 2, 3, 4}
-        0, 1, 2, 3, 4}; // message_data = {0, 1, 2, 3, 4}
     EventMessageDecoder decoder = new EventMessageDecoder();
     MetadataInputBuffer buffer = new MetadataInputBuffer();
     buffer.data = ByteBuffer.allocate(rawEmsgBody.length).put(rawEmsgBody);
+
     Metadata metadata = decoder.decode(buffer);
+
     assertThat(metadata.length()).isEqualTo(1);
     EventMessage eventMessage = (EventMessage) metadata.get(0);
     assertThat(eventMessage.schemeIdUri).isEqualTo("urn:test");

library/core/src/test/java/com/google/android/exoplayer2/metadata/emsg/EventMessageEncoderTest.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.emsg;
 
+import static com.google.android.exoplayer2.testutil.TestUtil.createByteArray;
+import static com.google.android.exoplayer2.testutil.TestUtil.joinByteArrays;
 import static com.google.common.truth.Truth.assertThat;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -29,67 +31,52 @@ import org.junit.runner.RunWith;
 @RunWith(AndroidJUnit4.class)
 public final class EventMessageEncoderTest {
 
+  private static final EventMessage DECODED_MESSAGE =
+      new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
+
+  private static final byte[] ENCODED_MESSAGE =
+      joinByteArrays(
+          createByteArray(117, 114, 110, 58, 116, 101, 115, 116, 0), // scheme_id_uri = "urn:test"
+          createByteArray(49, 50, 51, 0), // value = "123"
+          createByteArray(0, 0, 11, 184), // event_duration_ms = 3000
+          createByteArray(0, 15, 67, 211), // id = 1000403
+          createByteArray(0, 1, 2, 3, 4)); // message_data = {0, 1, 2, 3, 4}
+
   @Test
   public void testEncodeEventStream() throws IOException {
-    EventMessage eventMessage =
+    byte[] foo = new byte[] {1, 2, 3};
-        new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
+
-    byte[] expectedEmsgBody =
+    byte[] encodedByteArray = new EventMessageEncoder().encode(DECODED_MESSAGE);
-        new byte[] {
+    assertThat(encodedByteArray).isEqualTo(ENCODED_MESSAGE);
-          117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
-          49, 50, 51, 0, // value = "123"
-          0, 0, 3, -24, // timescale = 1000
-          0, 0, 0, 0, // presentation_time_delta = 0
-          0, 0, 11, -72, // event_duration = 3000
-          0, 15, 67, -45, // id = 1000403
-          0, 1, 2, 3, 4
-        }; // message_data = {0, 1, 2, 3, 4}
-    byte[] encodedByteArray = new EventMessageEncoder().encode(eventMessage);
-    assertThat(encodedByteArray).isEqualTo(expectedEmsgBody);
   }
 
   @Test
   public void testEncodeDecodeEventStream() throws IOException {
-    EventMessage expectedEmsg =
+    byte[] encodedByteArray = new EventMessageEncoder().encode(DECODED_MESSAGE);
-        new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
-    byte[] encodedByteArray = new EventMessageEncoder().encode(expectedEmsg);
     MetadataInputBuffer buffer = new MetadataInputBuffer();
     buffer.data = ByteBuffer.allocate(encodedByteArray.length).put(encodedByteArray);
 
     EventMessageDecoder decoder = new EventMessageDecoder();
     Metadata metadata = decoder.decode(buffer);
     assertThat(metadata.length()).isEqualTo(1);
-    assertThat(metadata.get(0)).isEqualTo(expectedEmsg);
+    assertThat(metadata.get(0)).isEqualTo(DECODED_MESSAGE);
   }
 
   @Test
   public void testEncodeEventStreamMultipleTimesWorkingCorrectly() throws IOException {
-    EventMessage eventMessage =
-        new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
-    byte[] expectedEmsgBody =
-        new byte[] {
-          117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
-          49, 50, 51, 0, // value = "123"
-          0, 0, 3, -24, // timescale = 1000
-          0, 0, 0, 0, // presentation_time_delta = 0
-          0, 0, 11, -72, // event_duration = 3000
-          0, 15, 67, -45, // id = 1000403
-          0, 1, 2, 3, 4
-        }; // message_data = {0, 1, 2, 3, 4}
     EventMessage eventMessage1 =
         new EventMessage("urn:test", "123", 3000, 1000402, new byte[] {4, 3, 2, 1, 0});
     byte[] expectedEmsgBody1 =
-        new byte[] {
+        joinByteArrays(
-          117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
+            createByteArray(117, 114, 110, 58, 116, 101, 115, 116, 0), // scheme_id_uri = "urn:test"
-          49, 50, 51, 0, // value = "123"
+            createByteArray(49, 50, 51, 0), // value = "123"
-          0, 0, 3, -24, // timescale = 1000
+            createByteArray(0, 0, 11, 184), // event_duration_ms = 3000
-          0, 0, 0, 0, // presentation_time_delta = 0
+            createByteArray(0, 15, 67, 210), // id = 1000402
-          0, 0, 11, -72, // event_duration = 3000
+            createByteArray(4, 3, 2, 1, 0)); // message_data = {4, 3, 2, 1, 0}
-          0, 15, 67, -46, // id = 1000402
+
-          4, 3, 2, 1, 0
-        }; // message_data = {4, 3, 2, 1, 0}
     EventMessageEncoder eventMessageEncoder = new EventMessageEncoder();
-    byte[] encodedByteArray = eventMessageEncoder.encode(eventMessage);
+    byte[] encodedByteArray = eventMessageEncoder.encode(DECODED_MESSAGE);
-    assertThat(encodedByteArray).isEqualTo(expectedEmsgBody);
+    assertThat(encodedByteArray).isEqualTo(ENCODED_MESSAGE);
     byte[] encodedByteArray1 = eventMessageEncoder.encode(eventMessage1);
     assertThat(encodedByteArray1).isEqualTo(expectedEmsgBody1);
   }